Puzzle 5 Send It to the Printer

Python Brain Teasers — by Miki Tebeka (14 / 40)

👈 A Task to Do | TOC | Spam, Spam, Spam 👉

printer.py

​1: ​from​ ​threading​ ​import​ Thread
​- ​from​ ​time​ ​import​ sleep
​- 
​- 
​5: ​def​ ​printer​():
​-     ​for​ i ​in​ range(3):
​-         ​print​(i, end=​' '​)
​-         sleep(0.1)
​- 
​10: 
​- thr = Thread(target=printer, daemon=True)  
​- thr.start()
​- ​print​()  ​# Add newline​

Guess the Output

IMPORTANT

Try to guess what the output is before moving to the next page.

This code will print: 0

Output

WARNING

Due to the unpredictable nature of threads, this code might not print anything.

In line 11, you start a daemon thread.

The Python documentation says

The entire Python program exits when no alive non-daemon threads are left.

Since after the print() line there are no more non-daemon threads running, the process will exit. printer…